One of my two problems is this (see also my other post): Every time I start the programme, I get a pop-up reading User Account Control Do you want to allow this app form an unknown publisher to make changes to your PC. Well, I only have to click on YES and the programme will start, but I wish there was a way this does not pop.

Outlook Express needs administrative privileges to run correctly. Most likely the user on your computer does not have administrative privileges and that's why it is asking for administrator password.
You can try creating a shortcut on msimn.exe and run it from there ,will run without administrative privileges but some setting may not work.